Signal distortions can give rise to magnitude and phase errors and, thus, can negatively impact integrated circuit performance. For example, harmonic signal distortions are generated on a signal at an output of a circuit element (e.g., at an output of a metal or polysilicon signal wire or device) when the load at the input to that circuit element is non-linear. The magnitude of the distortion will depend upon the relative size of the non-linear load, the characteristics of the circuit element at issue and the source impedance. Harmonic distortion can change the shape of the output waveform of a signal from the fundamental waveform to a more complex shape and, thus, can impact the signal integrity such that the signal becomes misunderstood by a receiver. Additionally, the Federal Communications Commission (FCC) has set limits (i.e., specifications) on harmonics generation in radio (RE) applications to reduce interference between signals. Unfortunately, current integrated circuit performance modeling techniques do not adequately model substrate-generated signal distortions and, particularly, substrate-generated harmonic signal distortions. Therefore, there is a need in the art for an improved integrated circuit performance modeling technique that includes substrate-generated signal distortions and, particularly, substrate-generated harmonic signal distortions.